Apraxia is a neurological disorder. In general, the diagnostic term "apraxia" can be used to classify the inability of a person to perform voluntary and skillful movements of one or more body parts, even though there
The term apraxia is derived from the Greek word praxis, which refers to producing an action or movement. In 1861, Broca described in detail an 84-year-old man who suffered a sudden impairment of speech production, but preservation of oral musculature functions, overall language skills, and intelligence. Broca coined the term "aphemia" to classify the inability to articulate words in the presence of a good language foundation. In 1900, Leipmann reported a 48-year-old patient who was unable to execute various voluntary motor behaviors of the limbs and oral cavity, despite good muscle strength, intactness of certain automatic or previously well-rehearsed speech or bodily movements, and complete understanding of the intended acts. Liepmann popularized the diagnostic term "apraxia" to differentiate individuals with these types of select motor difficulties from those who struggle with movement disturbances because of weakness, paralysis, and incoordination of the muscles involved.
There are no undisputed figures regarding the incidence of apraxia in the general population. However, because strokes are common causes, and African-American men are more susceptible to the development of this disease, by default this population may be at the greatest risk for this neurological disorder.
Causes and symptoms
Based on many additional case studies, Liepmann suggested that there are three major types of apraxia, each of which is caused by different sites of brain damage: ideational, ideo-motor, and kinetic.
Autopsy examinations and magnetic resonance imaging (MRI) scans have demonstrated that, in general, individuals with ideational, ideo-motor, and kinetic apraxias have pathologies involving either the back (parietal-occipital), middle (parietal), or front (frontal) lobes of the cerebral cortex, respectively. The individual with ideational apraxia cannot consistently produce complex serial actions, particularly with objects, due to disruptions at the conceptual stage of motor planning where the purpose and desire to perform specific movements are formulated. This
individual may begin an act with a set purpose and start its performance, but then suddenly cease because the original goal is forgotten. The primary problem is failure to form concepts and/or inability to retain the conceptual plan for a sufficient period of time to allow the desired movements to be effectively programmed and executed. For example, if patients with ideational apraxia are requested to demonstrate proper use of a toothbrush, they might first brush their nails, then hesitate and brush their pants, and finally, with prompting, brush their teeth. Their actions will likely be slow and disorganized, appearing as though they have to think out each movement along the way.
Ideo-motor apraxia is characterized by derailments of bodily movement patterns, due to disturbances in the motor planning stages of a well-conceived behavioral act. Breakdowns most often occur during verbal commands to use objects rather than when the same objects are being used spontaneously. The patient with this disorder fails to translate the idea to perform specific movements into a coordinated and sequential scheme of muscle contractions to achieve the desired motor goal. If asked to demonstrate use of a pair of scissors, unlike ideational apraxics, individuals with ideo-motor apraxia will not make the mistake of using this tool as if it were a screwdriver. Rather, they might grasp the scissors with both hands and repetitively open and close the blades, or pick up the paper in one hand and the scissors in the other and rub them against one another with hesitant motions.
Kinetic apraxia is characterized by coarse, clumsy, groping, and mutilated movement patterns, especially on tasks that require simultaneous, sequential, and smooth contractions of separate muscle groups. These disturbances are usually proportional to the complexity of the task. The disorder does not involve ideation or concept formation, as the desired movement is almost always evident in the struggle. Typing, playing a musical instrument, and handwriting tasks are very difficult for the individual with kinetic apraxia. The problem is not with preliminary motor planning, as in ideo-motor apraxia. Instead, the kinetic apraxic suffers from disturbances in programming the motor plan into subunits of sequential muscle behaviors. Normally, such instructions are then conveyed directly to the primary motor system, which in turn initiates neural commands necessary to execute the intended act.
Apraxia of speech is a subtype of kinetic apraxia. This disorder is often observed following damage to the brain in an area named after Broca. Not infrequently, speech apraxia co-occurs with notable language disturbances, known as aphasia. Individuals with speech apraxia struggle with dysfluent articulation problems, as they grope to posture correctly sequential tongue, lip, and jaw movements during speech activities. Numerous, but variable articulatory errors occur, characterized by false starts, re-starts, sound substitutions, sound and word repetitions, and overall slow rate of speech. Multisyllabic words and complex word combinations are most vulnerable to these types of breakdowns.
Testing for apraxia should employ basic screening tasks to identify individuals who do and do not require deeper testing for the differential diagnosis. Basic limb and orofacial praxis measures include the following commands:
- blow out a match
- protrude the tongue
- wave goodbye
- brush the teeth
- flip a coin
- hammer a nail into wood
- cut paper with scissors
- tap the foot
- stand like a golfer
- jump up and down in place
- thread a needle
- tie a necktie
- recite isolated words, word sequences, and phrases
More detailed testing usually includes many additional tasks of increasing motor complexity.
Because the apraxias are neurological disorders, a clinical neurologist is often the team leader. A neurosurgeon may also be on the team, especially if the underlying cause requires surgical attention. Likewise, the primary medical care practitioner plays a very important role in taking care of the individual's overall health-related needs. The responsibilities of the nurse and clinical psychologist should not be underestimated, as many apraxic individuals experience the need for hospitalization, financial aid, social reintegration, and emotional and family counseling. Speech-language and occupational therapists are also key team members in those cases with clinically significant speech and/or limb-girdle movement abnormalities.
Occupational therapists may employ exercises to rehabilitate proper use of eating utensils, health care and hygiene products, and self-dressing skills. The speech therapist focuses on retraining fluent and articulate movement patterns to improve overall speech intelligibility. Specific exercises may include tongue, lip, and jaw rate and rhythm activities, as well as combinations of complex sound and word productions.
As of 2003, the National Institute of Neurological Disorders and Stroke (NINDS) sponsored two clinical trials that focused on patients with ideo-motor apraxia. These studies used different techniques to analyze brain activity as patients performed various movements and simple tasks.
The National Institute on Deafness and Other Communication Disorders (NIDCD) is also sponsoring a study. This clinical trial focuses on patients who experience speech and communication complications related to neurological illness.
Further information on these trials can be obtained by contacting the National Institutes of Health Patient Recruitment and Public Liaison Office.
The potential for significant improvements with treatments and self-healing (spontaneous recovery) are most likely in cases of mild apraxia with stable medical courses. For more severe cases, particularly those with progressive
People with apraxia who are elderly and/or who may also have co-morbid medical problems often require ongoing assistance with daily living activities. Nursing home facilities may be necessary for those individuals who do not have the opportunity or resources either to live by themselves or with family members, or to hire a home-based caregiver. Although apraxia most often afflicts adults, school-age children or adolescents with this disorder will require special education considerations and intensive academic and therapeutic programs.
Quality of life
Apraxia may be caused by very serious neurologic diseases or injuries. The quality of life of those afflicted with this disorder is usually influenced by its underlying cause. Many individuals have co-occurring physical, psychological, and intellectual disabilities, which complicate the differential diagnostic process and challenge the potential for meaningful rehabilitation and a fruitful quality of life. Others struggle with less intertwined functional disturbances. These individuals tend to lead more productive lives because they are not as severely impaired.
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Icon Health Publishers. The Official Patient's Sourcebook on Apraxia: A Revised and Updated Directory for the Internet Age. San Diego: Icon Group International, 2002.
Vellemen, Shelley L. Childhood Apraxia of Speech. San Diego: Singular Publishing, 2002.
Geschwind, N. "The Apraxia: Neural Mechanisms of Disorders of Learned Movement." American Scientist 63 (1975): 188.
Apraxia-Kids. Childhood Apraxia of Speech Association. December 9, 2003 (March 11, 2004). <www.apraxiakids.org>.
NINDS Apraxia Information Page. National Institute for Neurological Disorders and Stroke. December 17, 2001 (March 11, 2004). <http://www.ninds.nih.gov/health_and_medical/disorders/apraxia.htm>.
National Institute of Deafness and Other Communication Disorders. 31 Center Drive, MSC 2320, Bethesda, MD 20892. (800) 411-1222. firstname.lastname@example.org. <http://www.nidcd.nih.gov/>.
National Institutes of Health Patient Recruitment and Public Liaison Office. 9000 Rockville Pike, Bethesda, MD 20892. (800) 411-1222. email@example.com. <http://www.nih.gov/>.
National Institute of Neurological Disorders and Stroke. P.O. Box 5801, Bethesda, MD 20824. (301) 496-5751 or (800) 352-9424. <http://www.ninds.nih.gov>.
Wayne State University, Department of Otolaryngology, Head and Neck Surgery. 5E-UHC, 4201 St Antoine, Detroit, MI 48201. (313) 577-0804. <http://www.med.wayne.edu/otohns/index.htm>.
James Paul Dworkin, Ph.D.